ifr190329–069 Pre-Season Tar Spot Checklist for Corn Nathan Kleczewski, Extension Plant Pathologist - University of Illinois Tar spot is a relatively new disease of corn in the Midwest. Todd Gleason has this pre-season checklist for farmers, roughly speaking, north of Interstate 80. Tar spot has been showing up on field corn… 1:22 radio 1:28 radio self-contained Tar spot has been showing up on field corn in Iowa, Illinois, Michigan, Wisconsin, Indiana, Ohio, and Florida says University of Illinois Extension Plant Pathologist Nathan Kleczewski (kleh-CHEH-ski). Kleczewski :20 …where we’ve had the most pressure. Quote Summary - That’s where it is found right now. But in terms of severity, where we have seen it the most and the pressure is the highest, if you would take the lower portion of Lake Michigan and draw a section around there, that is where we’ve had the greatest severity right now. That is where we’ve had the most pressure. Kleczewski (kleh-CHEH-ski) says thi...